Harry Redknapp can appreciate the romance of the story and, under normal circumstances, he would have embraced it. His former club Portsmouth have endured a nightmarish season, in which financial meltdown and administration have provided the backdrop to looming relegation from the Premier League. The club have adopted the prefix of "crisis" throughout. Yet out of the misery and frustration, it feels as if some form of footballing providence is pulling them towards the FA Cup final and there will not be a neutral outside of Southampton who does not wish them well in their semi-final against Tottenham Hotspur at Wembley tomorrow.

Redknapp helped to script a fairytale in 2008, when he led Portsmouth to FA Cup glory over Cardiff City, having taken the scalp of Manchester United at Old Trafford along the way. It remains the only time since 1995 that a team outside the present day Big Four has won the Cup. In many respects, Redknapp helped to breathe the romance back into the competition. Now, with the boot most assuredly on the other foot, he must adopt the role of dream-wrecker. It is not something the Tottenham manager feels comfortable with.

"I was pleased that Portsmouth got through but I really didn't want to draw them," Redknapp said. "I was hoping to draw Aston Villa. I'm not saying that would have been an easy game but you would want to avoid Chelsea and I really didn't want to face Portsmouth."

Whereas Redknapp assembled a fine team on the open market to win the Cup with Portsmouth two years ago, Avram Grant has taken them to within touching distance of the final with a squad picked over by the vultures. Redknapp has been chief among them, having signed Jermain Defoe, Peter Crouch, Niko Kranjcar and Younes Kaboul from Pompey.

What irks Redknapp, however, is the accusation that his assembly of the Portsmouth team that brought joy and indelible memories contributed to the club's overstretching itself, to sending it towards the bottom of a pit from which it could not clamber out. He has frequently highlighted the massive profits he turned on Sulley Muntari, Lassana Diarra, Defoe and Glen Johnson, among others, and a close examination of all the deals during his second spell at the club reveals that his net spend was greatly in the black.

What about the player wage bill with which Redknapp saddled the club, ask the critics, a millstone that accounted for such a high proportion of turnover? Redknapp might counter that his dealing on the market helped to compensate or, more pertinently, that it was not his ultimate responsibility. Managers are not dissimilar to children in a sweet shop when it comes to new signings. They invariably want them all and, if they are not discouraged, they will keep on pushing their luck. A club's board of directors must be strong enough to say no.

"The problem was that the owner when I was there, Sacha Gaydamak, suddenly lost interest and stopped putting money in," Redknapp said. "They have not funded the club [since he left]. It only holds 19,000 people, there is no [corporate] hospitality. That's the trouble. And who knows where the money has gone? Who owns the land around the stadium? I wouldn't know."

Redknapp said that of his Cup-winning team: "Hermann Hreidarsson was a free from Charlton, Kanu was a free from Hackney Marshes and Sylvain Distin came on a free and they sold him to Everton for £5m-6m." He noted that Sol Campbell, another Bosman signing, might have been on good wages but "nowhere near what he was getting at Arsenal. It cost him so many millions to leave Arsenal to come to Portsmouth."

Redknapp also observed that Portsmouth had spent "decent money" last summer, well after his departure, despite people saying that they were "skint". "They paid £4m for [Kevin-Prince] Boateng, and £2m for the kid from Watford [Mike Williamson] who they sold for £800,000 in the next window," he said. "They bought [Nadir] Belhadj for £3m-£4m and [Tal] Ben Haim is on a big, long contract."

Having left Portsmouth twice, the first time for their rivals Southampton, Redknapp has made enemies of a section of the club's fan base. They tormented him with crank calls in the wake of his leaving for Tottenham while his return to Portsmouth to receive the freedom of the city for his FA Cup exploits was marred by the noisy minority. "It doesn't bother me if they have a pop," Redknapp said. "But I went back to Fratton Park [in October] and there weren't any problems. People got upset when I left because I did such a good job there. You always get some but 99% are fantastic."

Tottenham will start as the strong favourites, despite a raft of injury concerns, but Redknapp described Portsmouth as "dangerous" underdogs and he predicted that a host of their players would suddenly rediscover fitness. This is all that they have left this season.

"It's another game, it takes an awful lot to get me excited," Redknapp said, attempting to play down the occasion. "My foreign players don't get too excited, either. I'll walk up to them now and say: 'Are you excited?' and they'll just shrug. Benoît [Assou-Ekotto] doesn't even know we're playing at Wembley." For Redknapp, cold-hearted professionalism has to be the order of the day.